American Society of Nephrology, Oct. 30-Nov. 4, 2012

The annual meeting of the American Society of Nephrology was held from Oct. 30 to Nov. 4 in San Diego and attracted approximately 13,000 participants from around the world, including nephrology specialists, researchers, scientists, and other health care professionals. The conference featured presentations focusing on the latest advances in the management of patients with kidney diseases and related disorders.

In one study, Delphine Tuot, M.D., of the University of California in San Francisco, and colleagues found that differences in blood pressure (BP) control among patients with chronic kidney disease (CKD) of different races/ethnicities were smaller in the Community Health Network of San Francisco (CHNSF) compared to the national average. In addition, the CHNSF appears to provide more equitable care to patients with CKD compared to the national average.

"Overall, adjusted prevalence of uncontrolled BP among patients with CKD in the CHNSF is higher than national estimates (25.42 versus 21.72 percent). But, this differed by CKD severity. For CKD stages 1 and 2, prevalence of uncontrolled BP in the CHNSF was 18 percent, compared to 22 percent nationally; for CKD stages 3 and 4, prevalence of uncontrolled BP in the CHNSF was 28 percent, compared to 23 percent nationally," Tout said. "Public health delivery systems similar to the CHNSF may provide more equitable care for patients with CKD than national averages. And, they do a good job of controlling BP in patients with early CKD, despite caring for a population with high rates of poverty, limited health literacy, and non-English speakers."

In another study, Dorry Segev, M.D., Ph.D., of the Johns Hopkins Medical Institutions in Baltimore, and colleagues evaluated 1,046 individuals who donated kidneys at Johns Hopkins between 1970 and 2011 and compared them with matched, healthy controls drawn from two large cohort studies, where patients underwent extensive medical evaluation and follow-up.

"We found that live donors had 35 percent higher rates of hypertension compared with healthy controls. This effect was more pronounced in Caucasian donors versus African-American donors, which is interesting because it's African-American donors who we classically worry more about in regards to hypertension," Segev said. "In other words, African-American donors have higher rates of hypertension after kidney donation than Caucasian donors; however, our study suggests that this is not because of the donation but because African-Americans in general have higher rates of hypertension than Caucasians. Our findings are important for counseling individuals who are considering donation about the long-term risks associated with donation, but also are reassuring that African-Americans aren't more at risk for this effect than any other donors."

Nimrit Goraya, M.D., of the Texas A&M College of Medicine in Temple, and colleagues evaluated patients with hypertension associated CKD and metabolic acidosis (MA) with serum bicarbonate levels between 22 to 24 mmol/L to determine if intervention (fruits and vegetables or NaHCO3) was effective in reducing kidney injury parameters, glomerular filtration rate (GFR), and BP.

"Our data showed improvement in GFR decline and lowering of urinary angiotensinogen at levels of metabolic acidosis for which currently no treatment guidelines exist," said Goraya. "We need larger studies to support our finding; however, treatment of metabolic acidosis can be kidney protective."

Sindhu Chandran, M.D., of the University of California in San Francisco, and colleagues evaluated patients with prediabetes who donated a kidney approximately 10 years ago. The investigators found that only 11 percent of living kidney donors with prediabetes had developed diabetes at 10 years of follow-up. In addition, donors with prediabetes maintained good kidney function overall.

"The key conclusion is that, in the short term (10 years), donating a kidney appears to be safe for individuals with prediabetes," Chandran said. "Prediabetes affects 35 percent of the adult U.S. population, and by extension, one in three potential living kidney donors. By excluding all people with prediabetes, we may be unnecessarily restricting living kidney donation. If the results of our study are confirmed in larger cohorts and over longer follow-up, we will be able to safely increase the number of lifesaving organs donated to the 95,000 people with end-stage renal disease currently on the kidney transplant waiting list."

Vincente Torres, M.D., Ph.D., of the Mayo Clinic in Rochester, Minn., and colleagues evaluated the efficacy and safety of tolvaptan in treating autosomal dominant polycystic kidney disease (ADPKD) and the complications it causes in patients affected by the disease.

"The trial results show that tolvaptan, given over three years, slowed the increase in kidney volume and the decline in kidney function. Kidney pain, hematuria (bloody urine), and urinary tract infections -- complications associated with ADPKD -- occurred less frequently in the patients treated with tolvaptan compared to those treated with placebo," Torres said. "The most common adverse effects in patients who received tolvaptan were anticipated and related to high urine output with more frequent voiding. Unexpected liver test abnormalities were observed in approximately 5 percent of patients and will need to be monitored."

Otsuka Pharmaceuticals, the manufacturer of tolvaptan, sponsored the trial.